As the need for information and entertainment by consumers grows, various pipelines have been developed to deliver this data to the different subscribers and users. A pipeline is a system that communicates data from a data provider (e.g., a television station, website on the Internet) to a subscriber. One current pipeline used by Internet service providers such as AmericaOnLine is the telephony system. The subscribers use a computer modem to connect to the Internet service provider over the telephony system. This system, however, is often ineffective for conveying large quantities of data because of bandwidth limitations. Some subscribers have installed higher-speed telephonic connections but due to the associated costs this practice is not widespread.
Other pipelines deliver data with varying degrees of success. Conventionally, television stations use a wireless pipeline for its delivery system. The stations broadcast a signal in a dedicated portion of the electromagnetic spectrum and subscribers access the signal with roof-top antennas. Another conventional pipeline is the cable system which uses coaxial cable to deliver video with increased quality and quantity. Recent advances in the cable standards and products including the two-way cable modems have provided two-way communication between the service provider and the subscribers. In addition to the television broadcasting, this advance does allow for Internet access and telephony service over the traditional cable systems.
Recently, the industry has designed various types of fixed point to multipoint wireless systems which provide both one-way and two-way communications. One example of these types of systems is the Multichannel Multipoint Distribution Service (MMDS), traditionally used for television broadcasting. There has also been development of the Wireless Loop systems, providing a cost-efficient alternative to the copper wires in the local loop (i.e., the last segment in the telephony network deployment). Additionally, the Federal Communication Commission (FCC) recently approved the two-way use of MMDS thereby allowing a wide variety of interactive services within the MMDS spectrum including classic telephony, Internet access, data for business applications and interactive video.
Moreover, the FCC has also recently auctioned off a large amount of bandwidth (1.3 GHz) for two-way applications in the frequency range of 28 to 31 GHz known as Local Multipoint Distribution System (LMDS). Internationally LMDS is also employed under different names and at various frequencies within the range of 10 to 40 GHz for both one-way and two-way communications. As both the MMDS and LMDS employ wide bandwidth with the ability to deliver large amounts of information, they are categorized as broadband wireless systems. Because wireless systems like MMDS and LMDS as well as others have limited bandwidth availability while also providing broadband services to their users, these systems need an efficient solution to the basic capacity problem.
Another issue unique to wireless systems exists which must be addressed when providing any solution to this limited capacity problem. As the radio waves propagate in open space, the transmissions of one link may interfere with the transmissions from another link operating on the same frequency channel. This problem limits the frequency reuse in wireless systems deployment. In order to reuse the same frequency channel at different areas, it is necessary to provide sufficient separation between the different areas that use the same frequency band which thereby limits interference in the different areas.
Currently this separation can be achieved by distancing the areas from one another through sectorization and/or polarization. Sectorization is the process of using directive antennas in sectors within the different communications areas. Polarization provides for the communicating of a signal with a different polarization in the different areas of frequency reuse by implementing differently polarized antennas within the different communication areas.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a communication system in a limited frequency spectrum which provides for enhancements in capacity through better frequency reuse and by allowing a process of gradually increasing capacity and sectorization while minimizing the associated costs.